It’s not always easy to know when your cat should see a veterinarian, in part because cats are masterful at disguising illnesses and injuries. Whether you turn to books, the Internet, your personal experience or veterinarians, be sure to look out for certain health signs.

Cat Health ResourcesThe first step for most cat owners is noticing something’s amiss, whether your pet is eating less, urinating outside the litter box or sneezing. Although it’s natural to try to figure out what’s going on before you make that veterinary appointment, first and foremost, just call your veterinarian, says Dr. Annie Price, owner of Ormewood Animal Hospital in Atlanta.

Educating yourself about cat behavior and the symptoms of illness is helpful as well. The American Association of Feline Practitioners offers good advice at CatVets.com and HealthyCatsForLife.com. Cornell University’s College of Veterinary Medicine also provides useful information about cat health at www.Vet.Cornell.edu . The university offers phone consultations three days a week, but each consultation costs $55. Plus, it may take up to 48 hours from the time you place the initial call until your consultation.

Whether you read cat health books or take first aid classes for pet owners, educating yourself can help you become more attuned to health indicators that are easy to overlook. “Because cat owners are around their cats daily, subtle changes or gradual changes can be missed,” says Dr. Joanne Gaines, owner of Ridgeview Animal Hospital in Omaha, Neb. “Increases in drinking and urination and weight loss are the most common gradual changes we see, and those changes can be caused by thyroid disease, kidney or liver disease or diabetes, most commonly.”

It’s best to let your veterinarian help you determine when a visit is in order, but Price and Gaines offer these helpful guides:

Keep a watchful eye. If your cat expels an occasional hairball, it’s probably not significant, says Price. “One hairball, a little regurgitation of food -- it happens,” she says. A few sneezes here and there may be something to monitor, but should not require a veterinary visit. Cats occasionally will have a runny eye that should resolve itself. If your cat snoozes more after an active day, it is probably just tired. Your cat might not eat as enthusiastically once in a while, but note if it’s becoming a pattern of behavior.

Schedule an appointment. Continued vomiting or diarrhea, poor grooming habits, a regular eye discharge or a squinting eye, increased water intake, increased urination, a runny nose and regular sneezing are among the indicators that your cat should see a veterinarian, say Gaines and Price. Sick cats will often sleep or hide more, notes Price. She particularly cautions against mistaking urinating outside the litter box as spiteful behavior. “A lot of people assume it’s behavioral or revenge, but that can mean a simple urinary tract infection, or your cat could be developing kidney problems or metabolic problems,” says Price.

If your cat becomes more vocal or begins grooming less, schedule an exam. “Anything subtle and different is something to take note of,” says Price. A change in personality, such as aggressive behavior, warrants a veterinary appointment.

Get your cat to the veterinarian immediately. “Emergency situations include straining to urinate, trouble breathing, bleeding, severe lethargy and most things relating to the eyes,” says Gaines. If you feel your cat’s health situation is urgent, don’t hesitate. Rapid breathing should be checked immediately as well, advises Price. “If your cat appears to be suffering a seizure, get it to the veterinarian right away,” she cautions.

Scheduling regular veterinary visits is the safest way to monitor your cat’s health. “Physical exams on a regular basis are so important. I always recommend once a year. There’s so much we can see just in a physical, tip of the nose to the tip of the tail,” says Price.